25 Things I Learned About Life By Age 25

When I turned 25, I wrote down some of the things I've learned over my short time on earth. The last year has been a crazy roller-coaster ride which has enabled me to see certain things like never before.Last year during this time, I was working at what I would consider my "dream job" — well, before I discovered my current "job" (I don't think I can even call it a job).

Over the last year, I've tried to learn from people who have "made it" in life — entrepreneurs, figureheads, lawyers, bankers and even politicians. I've realized that there is no formula to success in life, but there are definitely lessons that can be learned to help along the journey. I came up with the following list which I hope to someday come back to — but for now, I think it's a pretty accurate depiction of how I think. So without further adieu:

1. Take risks when you're young. The older you become, the harder it gets. But they should always be calculated.

2. The most important thing you learn in school is how to learn. Once you master that, nothing will stand in your way. Never stop learning.

How to check AA/AAA alkaline battery using a Multimeter

We all run into a situation when batteries in our remotes, toys, keyboards/mice run out. If we don't know how to check a battery we might throw out a perfectly fine battery (especially when we have a pile of them somewhere in the drawer).

This electronics tip has to deal with checking common alkaline AA/AAA batteries or AA/AAA rechargeable batteries for proper voltage with a voltmeter.

Disclaimer : some people might say that a battery should always be tested under load but I have found that in most common household applications this is insignificant and will not change the results of the testing too much.

Things that you will need :
+ Multimeter/Voltmeter
+ Alkaline battery

Basic facts :
The proper voltage for AA/AAA alkaline battery is 1.5V
The proper voltage for AA/AAA NiCd/NiMh rechargeable battery is 1.25 Volts

Sin, cos & tan table | easy to remember

Understanding of Railway availiability figures

Understanding availability figures

When you finally get down to booking tickets, you will probably encounter several puzzling availability figures online. After all, finding out that your train and class is "PQWL5/WL5" for the 8th of December isn't very illuminating - what do these figures mean?  Worry not, help is at hand in the form of this tutorial.
There are several different websites you can use to get availability stats for trains, and this tutorial is especially applicable to these four:

• The official Indianrail website,
• Erail, 
• India Rail Info, and
• IRCTC

Websites like 90di and Cleartrip display availability figures in a slightly different (and simpler) format.  If you plan to stick to only these websites, you might not need this tutorial - you can head straight to the glossary to understand what the terms RAC and waitlist mean.
All screenshots from this tutorial are from Erail, and this tutorial assumes you already know how to read (though not interpret) availability figures displayed on the four sites mentioned earlier.  If not, you can always recap at this link.

[a] Figures like AVAILABLE 75
When seats or berths are available in your train/class, it is fairly simple to understand them.  The AVAILABLE means that seats/berths are available (duh), and the number following the AVAILABLE tells you exactly how many seats/berths are available.  Look at the image below:

Screenshot from www.erail.in
In this case, should I want to travel by First AC (1A) on the 21st of October, I don't have to worry too much as 75 seats are available at the moment.

[b] Figures like RAC87/RAC 74
On trains with sleeping accommodation, after all confirmed berths have been sold out, passengers are usually placed on an RAC ("Reservation Against Cancellation") list.  Being on the RAC list guarantees you a place on the train, with a small catch - you are guaranteed only a seat on the train.  If enough passengers cancel, you will be allotted a sleeping-berth.  
The following image is one for a train-class-date combination that has now reached the RAC list:

Screenshot from www.erail.in
So if I decide to travel by Sleeper Class (SL) on this train on the 8th of November, I will be placed on the RAC list.
Hold on, you might say.  Why are there two sets of numbers?  Why is it RAC87/RAC 74, and what position on the RAC list will you get - 87 or 74?  Good questions. The first number indicates the serial waitlist or RAC position; the second, the running waitlist or RAC position.  I suspect this clears nothing up for you; I'll simplify it a bit more.
The serial number (the first of the two) indicates your position in the queue since the waitlist/RAC list started, and your serial number will never change.  So in this case, all confirmed berths have been sold out, and you are the 87th person to join the queue after the RAC list started.  The second number (the running waitlist/RAC list number) is more important - it denotes the position you currently are at in the waitlist or RAC list.  As and when people cancel their tickets, your running waitlist/RAC list number will reduce until your ticket gets confirmed (if that happens).  So the first number denotes the position you would have been at in the waitlist/RAC list had no cancellations occurred.  So in this case, you would have been RAC87, but as 13 people have cancelled their tickets since the RAC list started, you will be RAC 74 if you book a ticket now.
So why two numbers, you might ask.  Why not just keep the running waitlist number and avoid all confusion?  Well, having two numbers does serve a purpose.  For many passengers who cannot access the net or use technology to find out which coach and berth they've finally been allotted, the only way to check before boarding the train is to look at the charts pasted at the station.  Checking your serial waitlist number on the list is easy - only one person can have a serial RAC position of 87, so all s/he needs to do is look for that entry in the chart.  On the other hand, many people will have the running RAC position of 74 at different times, which makes searching for the entry on the chart significantly more difficult.
Another use of two numbers is that before making your booking, you can:

• tell how many passengers have already cancelled their tickets,
• look at cancellation trends for your train and class, which will help you predict its chances of confirmation with greater accuracy.

[c] Figures like GNWL16/WL4
Availability figures like the one seen below for AC Chair Car (CC) on the 1st of October can seem even more perplexing:

Screenshot from www.erail.in
You now (hopefully) recognise the two numbers - the first (16) is the serial position; the second (4), the running position.  But what do GNWL and WL mean?
Four-letter words (not that four-letter word!) when checking availability usually suggest that a waitlist has started.  In trains with sleeping accommodation, the order is usually as follows:

• If confirmed berths are available, you will be allotted one.
• Once all confirmed berths have been sold, you will be placed on the RAC list.
• Once all confirmed berths and RAC positions booked, you will be placed on the waitlist.

Keep in mind that there is no RAC for trains with sitting accommodation (the above screenshot is one such example), and even trains with sleeper accommodation might not have an RAC list depending on the particular quota.  There is no RAC list for First AC Sleeper either.  In all these cases, the availability status moves directly from AVAILABLE to a waitlist.
Back to the example above, the first word tells you that it is a waitlist as well as the type of waitlist.  Here are the types of waitlists you might encounter:

• GNWL (General Waitlist),
• CKWL (Tatkal Waitlist),
• RLWL (Remote Location Waitlist, also abbreviated RLGN),
• PQWL (Pooled Quota Waitlist),
• RSWL (Roadside Waitlist)

Different waitlists have different chances of confirmation, so don't ignore this list.  Of all these waitlists, PQWL and RSWL are particularly difficult to get confirmed, with GNWL being the most likely to see confirmations.
Quotas like the foreign tourist quota, the ladies quota, the senior citizen quota, the defence quota and the physically handicapped quota have no waitlists.  Once all confirmed seats or berths have been sold from these quotas, the status changes directly to NOT AVAILABLE.
To wrap up this example, if you book this ticket, you will be 4th on the (general) waitlist.  Expecting four cancellations from other passengers is not too unreasonable in this case, and this ticket will probably get confirmed.

[d] Figures like REGRET/WL300
If I wanted to buy a ticket in Sleeper Class (SL) on this train for the 3rd of November, I wouldn't get very far.

Screenshot from www.erail.in
If you see REGRET as an availability status while trying to book tickets, you're going to have to choose another train or class.  REGRET means that the train-class-date combination is so full that they've stopped issuing tickets even on the waitlist.  In short, the railways know there is no chance that such a high waitlist will get confirmed, so they're telling you to take your business elsewhere.

[e] Figures like GNWL/AVAILABLE
This is a slightly strange figure to see.  The first word suggests a waitlist, so why is there an AVAILABLE after that?
(First AC, 14th October)

Screenshot from www.erail.in
When you see WL/AVAILABLE (irrespective of what type of waitlist it is), it means that at least one seat or berth is available.  This status tells you that the train got full, and hence a waitlist was started, but due to cancellations, seats or berths are now available.  Annoyingly, it doesn't tell you exactly how many seats or berths are available, so the only assumption you can make is that one seat or berth is available.  Only after booking will you know for sure.
If you see WL/AVAILABLE for a train-class combination over a series of dates, it's probably because the railways have decided to add extra coaches of that class to the train - the resulting capacity expansion killing any waitlists.
Alright, that's all folks!

GATE 2015 EE Syllabus

1. ELECTRICAL ENGINEERING – EE

Engineering Mathematics

Linear Algebra: Matrix Algebra, Systems of linear equations, Eigen values and eigen vectors. Calculus: Mean value theorems, Theorems of integral calculus, Evaluation of definite and improper integrals, Partial Derivatives, Maxima and minima, Multiple integrals, Fourier series. Vector identities, Directional derivatives, Line, Surface and Volume integrals, Stokes, Gauss and Green's theorems. Differential equations: First order equation (linear and nonlinear), Higher order linear differential equations with constant coefficients, Method of variation of parameters, Cauchy's and Euler's equations, Initial and boundary value problems, Partial Differential Equations and variable separable method. Complex variables: Analytic functions, Cauchy's integral theorem and integral formula, Taylor's and Laurent' series, Residue theorem, solution integrals. Probability and Statistics: Sampling theorems, Conditional probability, Mean, median, mode and standard deviation, Random variables, Discrete and continuous distributions, Poisson, Normal and Binomial distribution, Correlation and regression analysis. Numerical Methods: Solutions of non-linear algebraic equations, single and multi-step methods for differential equations. Transform Theory: Fourier transform, Laplace transform, Z-transform.

GENERAL APTITUDE(GA):

Verbal Ability: English grammar, sentence completion, verbal analogies, word groups, instructions, critical reasoning and verbal deduction.

Electrical Engineering

Electric Circuits and Fields: Network graph, KCL, KVL, node and mesh analysis, transient response of dc and ac networks; sinusoidal steady-state analysis, resonance, basic filter concepts; ideal current and voltage sources, Thevenin's, Norton's and Superposition and Maximum Power Transfer theorems, two-port networks, three phase circuits; Gauss Theorem, electric field and potential due to point, line, plane and spherical charge distributions; Ampere's and Biot-Savart's laws; inductance; dielectrics; capacitance. Signals and Systems: Representation of continuous and discrete-time signals; shifting and scaling operations; linear, time-invariant and causal systems; Fourier series representation of continuous periodic signals; sampling theorem; Fourier, Laplace and Z transforms. Electrical Machines: Single phase transformer - equivalent circuit, phasor diagram, tests, regulation and efficiency; three phase transformers - connections, parallel operation; auto-transformer; energy conversion principles; DC machines - types, windings, generator characteristics, armature reaction and commutation, starting and speed control of motors; three phase induction motors - principles, types, performance characteristics, starting and speed control; single phase induction motors; synchronous machines - performance, regulation and parallel operation of generators, motor starting, characteristics and applications; servo and stepper motors. Power Systems: Basic power generation concepts; transmission line models and performance; cable performance, insulation; corona and radio interference; distribution systems; per-unit quantities; bus impedance and admittance matrices; load flow; voltage control; power factor correction; economic operation; symmetrical components; fault analysis; principles of over-current, differential and distance protection; solid state relays and digital protection; circuit breakers; system stability concepts, swing curves and equal area criterion; HVDC transmission and FACTS concepts. Control Systems: Principles of feedback; transfer function; block diagrams; steady-state errors; Routh and Niquist techniques; Bode plots; root loci; lag, lead and lead-lag compensation; state space model; state transition matrix, controllability and observability. Electrical and Electronic Measurements: Bridges and potentiometers; PMMC, moving iron, dynamometer and induction type instruments; measurement of voltage, current, power, energy and power factor; instrument transformers; digital voltmeters and multimeters; phase, time and frequency measurement; Q-meters; oscilloscopes; potentiometric recorders; error analysis. Analog and Digital Electronics: Characteristics of diodes, BJT, FET; amplifiers - biasing, equivalent circuit and frequency response; oscillators and feedback amplifiers; operational amplifiers - characteristics and applications; simple active filters; VCOs and timers; combinational and sequential logic circuits; multiplexer; Schmitt trigger; multi-vibrators; sample and hold circuits; A/D and D/A converters; 8-bit microprocessor basics, architecture, programming and interfacing. Power Electronics and Drives: Semiconductor power diodes, transistors, thyristors, triacs, GTOs, MOSFETs and IGBTs - static characteristics and principles of operation; triggering circuits; phase control rectifiers; bridge converters - fully controlled and half controlled; principles of choppers and inverters; basis concepts of adjustable speed dc and ac drives.